Journal of neurosurgery
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Journal of neurosurgery · Jun 2014
Multicenter StudyPressure autoregulation monitoring and cerebral perfusion pressure target recommendation in patients with severe traumatic brain injury based on minute-by-minute monitoring data.
In severe traumatic brain injury, a universal target for cerebral perfusion pressure (CPP) has been abandoned. Attempts to identify a dynamic CPP target based on the patient's cerebrovascular autoregulatory capacity have been promising so far. Bedside monitoring of pressure autoregulatory capacity has become possible by a number of methods, Czosnyka's pressure reactivity index (PRx) being the most frequently used. The PRx is calculated as the moving correlation coefficient between 40 consecutive 5-second averages of intracranial pressure (ICP) and mean arterial blood pressure (MABP) values. Plotting PRx against CPP produces a U-shaped curve in roughly two-thirds of monitoring time, with the bottom of this curve representing a CPP range corresponding with optimal autoregulatory capacity (CPPopt). In retrospective series, keeping CPP close to CPPopt corresponded with better outcomes. Monitoring of PRx requires high-frequency signal processing. The aim of the present study is to investigate how the processing of the information on cerebrovascular pressure reactivity that can be obtained from routine minute-by-minute ICP and MABP data can be enhanced to enable CPPopt recommendations that do not differ from those obtained by the PRx method, show the same associations with outcome, and can be generated in more than two-thirds of monitoring time. ⋯ Minute-by-minute ICP/MABP data contain relevant information for autoregulation monitoring. In this study, the authors' new method based on minute-by-minute data resolution allowed for CPPopt calculation in nearly the entire monitoring time. This will facilitate the use of pressure reactivity monitoring in all ICUs.
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Journal of neurosurgery · Jun 2014
ReviewAcute subdural hematoma from bridging vein rupture: a potential mechanism for growth.
Most acute subdural hematomas (ASDHs) develop after rupture of a bridging vein or veins. The anatomy of the bridging vein predisposes to its tearing within the border cell layer of the dura mater. Thus, the subdural hematoma actually forms within the dura. ⋯ Thus, the ASDH enlarges via a positive feedback mechanism. Enlargement of an ASDH would cease as blood within the hematoma cavity coagulates. This would stop the dissection of the dural border cell layer, and pressure within the hematoma cavity would equalize with that in the torn bridging vein or veins.
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Journal of neurosurgery · Jun 2014
Extracranial traumatic aneurysms due to blunt cerebrovascular injury.
Traumatic aneurysms occur in 10% of extracranial blunt traumatic cerebrovascular injuries (TCVI). The clinical consequences and optimal management of traumatic aneurysms are poorly understood. ⋯ The majority of traumatic aneurysms can be managed with an antiplatelet regimen of 325 mg aspirin daily and serial imaging. Saccular aneurysms have a greater tendency to enlarge when compared with fusiform aneurysms.
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Journal of neurosurgery · Jun 2014
Radiosurgery inhibition of the Notch signaling pathway in a rat model of arteriovenous malformations.
Notch signaling has been suggested to promote the development and maintenance of arteriovenous malformations (AVMs), but whether radiosurgery inhibits Notch signaling pathways in AVMs is unknown. The aim of this study was to examine molecular changes of Notch signaling pathways following radiosurgery and to explore mechanisms of radiosurgical obliteration of "nidus" vessels in a rat model of AVMs. ⋯ Radiosurgery inhibits endothelial Notch1 and Notch4 signaling pathways in nidus vessels while inducing thrombotic occlusion of nidus vessels in a rat model of AVMs. The underlying mechanisms of radiosurgery-induced AVM shrinkage could be a combination of suppressing Notch receptor signaling in blood vessel endothelial cells, leading to a reduction in nidus vessel size and thrombotic occlusion of nidus vessels.
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Journal of neurosurgery · Jun 2014
ReviewAnterior cerebral artery bypass for complex aneurysms: an experience with intracranial-intracranial reconstruction and review of bypass options.
The authors describe their experience with intracranial-to-intracranial (IC-IC) bypasses for complex anterior cerebral artery (ACA) aneurysms with giant size, dolichoectatic morphology, or intraluminal thrombus; they determine how others have addressed the limitations of ACA bypass; and they discuss clinical indications and microsurgical technique. ⋯ Anterior cerebral artery aneurysms requiring bypass are rare and can be revascularized in a variety of ways. Anterior cerebral artery aneurysms, more than any other aneurysms, require a thorough survey of patient-specific anatomy and microsurgical options before deciding on an individualized management strategy. The authors' experience demonstrates a preference for IC-IC reconstruction, but EC-IC bypasses are reported frequently in the literature. The authors conclude that ACA bypass with indirect aneurysm occlusion is a good alternative to direct clip reconstruction for complex ACA aneurysms.